Witchcraft of any type is an attempt to manipulate spiritual forces for our own purposes (either for good or for evil). It may use charms or incantations or other kinds of mystical practices to try to harness these spiritual powers, and people who start out with a casual curiosity about them often end up totally absorbed and unable to break free.
The Bible rejects all such practices, and strongly warns us against getting involved with them. The reason is because they seek power not from God but from spiritual forces that are actually opposed to God. The Bible reminds us that these spiritual forces are real, and they can be very destructive: "For our struggle is ... against the powers of this dark world and against the spiritual forces of evil in the heavenly realms" (Ephesians 6:12).
Pray for your friend, and ask God to help you talk with her frankly about her interest in the occult. Often people get involved in such things out of curiosity, without realizing the dangers that can result. Anything that turns us away from God and His plan for our lives is spiritually dangerous.
Encourage her instead to turn to Christ. Only He can satisfy the spiritual hunger in her heart, and only He can give us peace in the midst of life's storms. Urge her not to be deceived, but to put her faith and trust in Christ and His love.